To form a polyamide fiber material, polyamide resin, typically in the form of polyamide chips, is fed into an extruder, heated to a melt state, and pumped out through a spinneret (die) having multiple holes, also known as spinning, to form the polyamide filaments. The spun fibers, which contain the filaments, are solidified, and may be subjected to one or more drawing steps and collected on a take-up wheel. Typical polyamide materials include polyamide-6 (PA-6), polyamide-6,6 (PA-66), polyamide-666 (PA-666), polyamide-46 (PA-46), polyamide-610 (PA-610), and polyamide-1212 (PA-1212) materials.
Typical polyamide-6 materials are polymerized with mono-termination using a di-functional acid. During spinning the PA-6 material may be maintained in the melt state at about 230° C. to 300° C. for up to 5 to 45 minutes prior to being extruded from the spinneret. During this time at elevated temperature, the mono-terminated PA-6 material begins to thermally degrade, increasing the viscosity of the mono-terminated PA-6 material. The increase in viscosity leads to an increase in the spin pack pressure, which impacts the spinability and shortens the spin pack life of the mono-terminated PA-6 material. These deleterious effects may be especially seen in high speed spinning applications, such as for textiles.
Improvements in the foregoing processes are desired.